Heavy-duty stabilized camera head with camera position sensing

ABSTRACT

A panhead ( 1 ) having a counterbalance action suitable for heavy cameras or equipment, and provides instantaneous electronic measurements of head settings and position. The improved counterbalance utilizes a dual-tower dual-axis non-linear mechanism as well as position encoders indexed to each axis ( 7 - 13 ) of head movement. Potentiometer setting detectors are also indexed to settable adjustments to read and relay such adjustments, and an electronic display ( 25 ) conveys information regarding the current positions and settings of the camera head ( 1 ). A novel mounting system situated at the top of the head provides for fast and simple mounting and unmounting of equipment or a dutch roll head. In particular, a novel dovetail ( 19, 21 ) engagement mechanism swings a dovetail side down during detachment. In an embodiment of the invention, the dutch roll head can be remotely proportionally actuated by a user via a switch mountable to a handle used for panning and tilting of the pan head.

TECHNICAL FIELD

[0001] This invention relates generally to equipment for supportingoptical equipment and, more particularly, relates to a camera head forpivotally supporting a camera in a counterbalanced manner.

BACKGROUND OF THE INVENTION

[0002] Cameras have been and continue to be critical components in bothmotion picture and television feature production. An important criterionfor the use of a camera in television or motion picture capture tasks isthe ability to smoothly follow an action item, such as an athlete, withthe camera. However, cameras usable in motion picture and televisionwork are typically heavy and cumbersome to manipulate. For example, astandard television camera may weigh 100 pounds or more. Thus, in orderfor a camera to be manipulable so as to provide such smooth operation,it is desirable to balance the weight and inertia of the camera and tomitigate the effects of minor unintended forces on the camera by theoperator.

[0003] In order to stabilize the motion of a camera on a camera head, itis typical to employ drag mechanisms. One such prior art drag mechanismis illustrated in U.S. Pat. No. 4,955,568 (“the '568 patent”) toO'Connor et al, entitled “Panhead For Camera,” which is assigned to theassignee of the present invention and is hereby incorporated byreference in its entirety for all that it teaches. In particular, the'568 patent illustrates an adjustable fluid drag mechanism. It is usefulfor camera operators to have ready access to data describing the variousdrag settings for the camera, so as to accurately adjust such settingsand to be able to accurately reproduce a desired setting at a latertime. However, the mechanism illustrated in the '568 patent does notprovide for the rapid collection and display of measurement datarelating to the drag forces set by the operator. Other prior artmechanisms have also not provided integral mechanisms for sensing dragsettings and quickly conveying such settings to the camera operator in aunified way. Rather, prior art techniques have generally employed visualmechanical mechanisms that do not provide the level of accuracy,repeatability, and ease of use desirable in the motion picture industry.

[0004] Generally, counterbalance measures have been utilized to balancethe weight of the camera about the tilt axis. An example of aspring-operated counterbalance technique is described in the '568patent, previously incorporated by reference in its entirety. Othercounterbalance techniques have been employed as well. For example,counterbalances using linear springs or cam and roller architectureshave sometimes been employed.

[0005] However, prior art counterbalance techniques generally functionwell only for small to medium tilt angles. While the counterbalancemechanism disclosed in the '568 patent functions over a tilt angle of±90° and desirably exerts a sinusoidal restoring torque, none of theprior art techniques, including that of the mechanism disclosed in the'568 patent, are adapted and ideally suited for heavier cameras. Many ofthe cameras in use today for motion picture and television filming work,however, may far exceed 200 pounds in weight. For that reason, aheavy-duty counterbalance mechanism adapted to accommodate thecounterbalance loads produced by such equipment is needed.

[0006] Additionally, prior art mechanisms for attaching a camera orother equipment unit to a camera head are not suitable for use withheavy equipment. That is, they do not provide sufficient ease ofattachment and detachment for cameras that are cumbersome due to extremeweight. For example, a typical sliding dovetail connection requires auser to slide a heavy object along a precise axis while holding theobject level until support is achieved. Even systems that permit oneside of the dovetail base to drop away for camera removal still requiremanual intervention by the user to force the dropping side down.

[0007] In addition, it is often desirable for a camera operator or filmeditor to know the position of the camera throughout a shot or sequencein order to reproduce a scene or to coordinate special effects with theactual footage taken. The prior art, however, has not included means bywhich the camera operator could readily ascertain and thereby reproducethe exact position of the tripod and camera.

[0008] Accordingly, it is a general object of the invention to providean improved camera panhead that smoothly pans and tilts while allowinginstantaneous capture and display of camera position and drag settinginformation. A more specific object is to provide a head that providesthe instantaneous electronic capture and display of the camera positionand movement.

[0009] It is a further object of the invention to provide an improvedcamera panhead that is able to provide nonlinear counterbalance actionfor heavy cameras or other equipment throughout a wide range of tiltangles.

[0010] It is a further object of the invention to provide a camera headthat allows easy and accurate adjustment of the counterbalance and dragsettings.

[0011] It is a further object of the invention to provide an improvedcamera head that allows for the natural and uncomplicated mounting andremoval of heavy cameras or other equipment to the panhead.

SUMMARY OF THE INVENTION

[0012] The invention embodies in general terms an improved camerapanhead that provides counterbalance action suitable for heavy camerasor equipment, and that provides instantaneous electronic measurements ofhead settings and position. The improved counterbalance utilizes a noveldual-tower dual-axis non-linear mechanism to provide sufficientrestoring force and integrity to support heavy camera equipment, whilestill being relatively lightweight. The improved camera head alsoprovides high-accuracy absolute position rotary encoders indexed to eachaxis of head movement, as well as potentiometer setting detectorsindexed to settable adjustments. In this manner, both camera positionsand parameter adjustments may be electronically captured, recorded, anddisplayed to the user.

[0013] A conveniently placed electronic display conveys informationregarding the current state of the camera head. In particular, a digitalLCD graphical user interface is located on the head and displaysinformation relating to the position of the head and the position of thehead adjustment settings such as drag and counterbalance settings. Thedigital display is part of an electronics module that also containsvarious electrical inputs and outputs. A remote display module may beconnected to the electronics module via a cable to remotely display to auser data relating to the head.

[0014] A mounting platform situated at the top of the head provides forfast and simple mounting and unmounting of heavy equipment. Inparticular, a novel dovetail engagement mechanism provides forcompressive force by a movable dovetail side during attachment of thecamera. However, the novel dovetail engagement mechanism also swings thedovetail side down and away from the dovetail platform during detachmentto facilitate easy removal of the camera or other heavy equipment from adovetail base.

[0015] A dutch roll head attachment is mountable upon the mountingplatform and is adapted to receive the camera, thus providing anadditional axis of camera movement as well as positional information.

[0016] Additional features and advantages of the invention will be madeapparent from the following detailed description of illustrativeembodiments, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] While the appended claims will set forth the features of thepresent invention with particularity, the invention, together with itsobjects and advantages, may be best understood from the followingdetailed description taken in conjunction with the accompanying drawingsof which:

[0018]FIG. 1 is a perspective view of a camera panhead according toteachings of the present invention;

[0019]FIG. 2a is a cross sectional side view of a tilt axiscounterbalance mechanism;

[0020]FIG. 2b is a partial cross sectional top plan view of the tiltaxis counterbalance mechanism with the housing removed;

[0021]FIG. 3 is a cross sectional top view of the tilt axiscounterbalance adjustment mechanism;

[0022]FIG. 4a is a perspective view of a dutch roll head attachmentaccording to an embodiment of the present invention for use atop apanhead;

[0023]FIGS. 4b-d are side views of a dutch roll head attachmentaccording to an alternative embodiment of the present invention for useatop a panhead according to an embodiment of the invention, wherein thedutch roll head is shown in varying degrees of adjustment;

[0024]FIG. 4e is a perspective view of a dutch roll head attachmentaccording to an alternative embodiment of the present invention for useatop a panhead according to an embodiment of the invention.

[0025]FIG. 5 is a perspective view of an electronic module including adigital display according to an embodiment of the present invention;

[0026]FIG. 6 is a perspective view of an adjustable drag inducingmechanism according to an embodiment of the invention;

[0027]FIG. 7 is a perspective view of gearing used to actuate the tiltaxis counterbalance mechanism according to an embodiment of theinvention;

[0028]FIG. 8 is a fragmentary perspective view of a disc and associatedoptical pick-up for measuring camera position within an embodiment ofthe invention;

[0029]FIG. 9 is a cross sectional side view of the tilt axis draginducement and position measurement mechanisms;

[0030]FIG. 10 is a cross sectional side view of the pan axis draginducement and position measurement mechanisms;

[0031]FIG. 11 is a partial cross sectional side view of a dutch rollhead attachment according to an embodiment of the invention, showingdrag inducement, position sensing, and optional counterbalancelocations;

[0032]FIG. 12a is a cross sectional side view of a quick-change batterypack in an assembled position according to an embodiment of theinvention;

[0033]FIG. 12b is an exploded cross sectional side view of thequick-change battery pack in a disassembled position according to anembodiment of the invention;

[0034]FIG. 13 is an exploded perspective view of the quick-changebattery pack in a disassembled position according to an embodiment ofthe invention;

[0035]FIG. 14 is a partially exploded perspective view of an improveddovetail camera mounting system according to an embodiment of theinvention;

[0036]FIG. 15 is a cross sectional bottom view of the improved dovetailcamera mounting system according to an embodiment of the invention;

[0037]FIG. 16a is a fragmentary, partial cross sectional side view of adovetail side lowering mechanism according to an embodiment of theinvention with a dovetail side in a mating relation with a matching sideof a dovetail platform;

[0038]FIG. 16b is a fragmentary, partial cross sectional side view ofthe dovetail side lowering mechanism according to an embodiment of theinvention with the dovetail side in a withdrawn relation from thematching side of the dovetail platform;

[0039]FIG. 16c is a fragmentary partial cross sectional side view of thedovetail side lowering mechanism according to an embodiment of theinvention with the dovetail side in a withdrawn and lowered relationwith the matching side of the dovetail platform; and

[0040]FIG. 17 is a schematic diagram of a remote dutch roll head controlsystem according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0041] Turning to the drawings, wherein like reference numerals refer tolike elements, the invention is illustrated as being implemented inaccordance with teachings of the invention in a panhead as shown inFIG. 1. FIG. 1 shows a perspective view of a panhead 1 according to anembodiment of the invention. The illustration of FIG. 1 is generalized,and is intended to convey to the reader the general features and usageof the panhead in accordance with this embodiment. The panhead 1consists of a base 3 that is mountable to a tripod or other support,that in turn rests upon the ground or floor. The remainder of thepanhead, that is from housing 5 upward, is pivotable about a pan axis 7that runs substantially through the center or central region of the base3. This motion is damped and sensed, as will be discussed hereinafter.Locking lever 9 is operable to lock the panhead so that it does not moveabout the upright pan axis 7. It will be appreciated that the placementof this lever or any other control is not critical. Thus, for example,lever 9 may alternatively be located in a symmetric location on theopposite side of the head 1.

[0042] A housing 11 covers mechanisms related to the pivoting of thepanhead about a tilt axis 13, the mechanisms running substantiallyhorizontally through the center or central region of housing 11. Themotion of the head 1 about this axis is also sensed and damped as willbe discussed hereinafter. Locking lever 17 is operable to lock the headto prevent movement about tilt axis 13.

[0043] Situated at the top of the head 1 are structures to facilitatethe mounting of a camera or other equipment to the head 1. Inparticular, a dovetail base 19 is fixed to the housing 11, while adovetail platform 21 is fixable to the dovetail base 19 via two dovetailsides, one of which 23 is visible in FIG. 1, the other of which issymmetrically situated on the opposite side of the dovetail platform 21.Rather than mounting a camera directly to the dovetail base 19 via thedovetail platform 21, it is also possible to mount the camera to anotherattachment such as a dutch roll head as described herein, which is thenmounted to the dovetail base 19.

[0044] It will be appreciated that the placement of a heavy camera atopthe head 1 will create a significant downward force in the direction ofpan axis 7 when the camera is situated directly over the tilt axis 13.It will be further appreciated that any deviation of the center ofgravity of the camera from pan axis 7 will result in an increasingtorsional load about tilt axis 13 as the deviation increases. Thus, whena camera or other instrument supported on the platform 21 (or a dutchhead) is then tilted about the tilt axis 13, a significant and nonlinearrestoring force is required to counterbalance the camera so that theoperator is not required to constantly exert force to prevent the camerafrom pulling itself downward around tilt axis 13. In accordance with animportant aspect of the invention, the head 1 is provided with aheavy-duty nonlinear counterbalance mechanism.

[0045] Referring to FIG. 2, the counterbalance mechanism according to anembodiment of the invention is shown. FIG. 2a shows a sectional sideview of the counterbalance mechanism taken along tilt axis 13, whileFIG. 2b shows a cut-away top view of the mechanism taken along pan axis7, the housing 14 having been removed. While the structure describedherein is novel, the basic principle of operation of the counterbalancemechanism itself remains substantially the same as described in the '568patent to O'Connor et al., previously incorporated by reference.Accordingly, the function will be described only in overview except forthose portions that differ. For a more complete understanding of thegeometrical principles involved during use of the head, the reader isinvited to read the '568 patent, paying particular attention to thediscussion of FIGS. 6-10.

[0046] Referring to FIG. 2a, the lower portion of the panhead can beseen, as well as the dovetail base 19 for supporting equipment atop thehead 1. As described in greater detail in the '568 patent, the wiffletrees 201, 203 capture springs 205 in such a manner as to compress thesprings more or less depending upon the position of the base 19 as thehead is tilted. The reader is referred to FIGS. 8-10 of the '568 patentfor a discussion of the forces in play during tilting of the head.Essentially, the nonlinear deformation of the springs 205 creates anonlinear counterbalancing force to counter the nonlinear torsionalforce applied by the weight of the camera on the head during tilting.

[0047] However, for large heavy cameras, such as those weighing 200pounds or more, the counterbalance force that the springs 205 must exertbecomes immense. This creates a need for very powerful springs, eachcapable of exerting a restoring force of approximately 1000 pounds ormore, but the use of such powerful springs tends to place large loads onthe structural components of the head such as the rods 211 supportingthe trees 201, 203. Additionally, the force required to adjust thecounterbalance force by adjusting the position of the common rod 213 isgreatly increased generally in proportion to the increase in springstrength.

[0048] The solution of the present invention is to employ strong yetcompact compression springs, adapted to meet the large loads imposed,and being disposed in a novel arrangement to avoid damage to othercomponents of the head. In particular, in order to minimize the weightof the finished head, it is desirable to use hollow steel rods 211, 213,produced from 4130 heat-treatable alloy steel or other high strengthsteel or alloy. The reason for using hollow steel rods is that otherlightweight metals such as aluminum typically do not possess thestructural strength of heavier metals such as stainless steel, chromemolybdenum alloys, and other alloys.

[0049] Even so, in order to reduce the weight of the head whileaccommodating the structural loads imposed by the strong springs used,it is desirable to reduce the permissible size of the rods by arrangingthe spring loading to reduce the exerted rod bending moment. Referringto FIG. 2b, an exemplary wiffle tree arrangement according to thepresent invention is shown. In particular, the illustrated arrangementis devised to minimize bending moments by minimizing the distancebetween oppositely acting force centers on the most susceptibleelements, i.e. rods 211, 213.

[0050] Two support towers 215, 217 for the common rod 213 are provided,approximately symmetrically placed on rod 213, extending downward in thedirection of pan axis 7. It will be appreciated that the dual towerarrangement is also particularly suitable for use in an application suchas this, where extremely high force springs are utilized. The bendingmoment applied to the common rod 213 is reduced by providing the dualsupport towers 215, 217, thus reducing the necessary size and weight ofthe common rod 213. To readily adjust for equipment of varied weights,these towers are vertically adjustable to adjust the position of thecommon axis or rod 213. This way, the operator may adjust thecounterbalance force provided (according to the basic principles setforth in the '568 patent, already incorporated herein by reference inits entirety).

[0051] The spring assemblies are arranged as shown, so that the supporttowers are placed between oppositely extending wiffle tree and springassemblies, which are disposed at an angle with respect to pan axis 7.Additionally, the wiffle trees and support towers are disposed in arelationship that minimizes the bending moments, and, therefore,stresses along the shafts. More specifically, the wiffle tree pairingsare identical, rather than mirror images of each other across the centerof the head along the tilt axis as in the prior art. That is, the wiffletrees are disposed in a staggered fashion as opposed to symmetricallyabout a central support tower, as disclosed in the '568 patent. In thisway, the two central wiffle tree assemblies place the greatest bendingload on their respective wiffle tree support rods 211. However, unlikethe prior art, the other wiffle tree assembly on each support rod 211provides minimal additional bending load because each is placed adjacenta support point, i.e. end wall 207 or end wall 209. With respect to theloads experienced by common rod 213, the bending loads are alsominimized by the illustrated configuration. In particular, lower wiffletree supports 203 are placed so as to minimize the distance between themand any adjacent support points such as support towers 215, 217 or endwalls 207, 209. In addition, the close spacing of opposing lower wiffletree supports 203 minimizes the local twisting moment resulting frompairs of oppositely directed horizontal force components applied on rod213 by adjacent lower wiffle tree support pairs. In other words, thestaggered positioning of the wiffle tree supports 201, 203 along therespective support rods 211 and common rod 213 minimize the resultingbending moments exerted by the two centermost wiffle tree supports 201,203.

[0052] Note that the foregoing discussion describes a preferredarrangement for two pairs of spring assemblies used in counterbalancing,however, the two pairs of spring assemblies may alternatively bearranged in another configuration. Exemplary alternative configurationsare shown in FIGS. 12 and 13 of the '568 patent (for two springassemblies) already incorporated herein, and are described in therelated discussion in the '568 patent. Given the disclosure herein, oneof skill in the art will appreciate that the same mechanisms may beadapted for the use of two pairs of spring assemblies.

[0053]FIG. 3 illustrates an exemplary mechanism by which the supporttowers 215, 217 of FIG. 2 may be adjusted upwardly and downwardly alongpan axis 7 without the application of undue force by the operator. Inparticular, FIG. 3 illustrates a partial cross sectional view of thepanhead at line A taken along pan axis 7 of FIG. 2a. It can be seen thatsupport towers 215, 217 are centered on circular gears 301, 303.Respective threaded shafts 302, 304 fixed to each of gears 301, 303extend perpendicular to each gear's major plane and extend threadablyinto each of support towers 215, 217. Thus, a turning of the gears 301,303 results in a raising or lowering of the support towers 215, 217.Even though this relationship provides a certain leverage advantagedepending upon the thread pitch of the threaded shafts 302, 304 fixed tothe circular gears 301, 303, the strength of the springs 205 is suchthat greater leverage may be needed by many human operators.Accordingly, the gears 301, 303 are driven and coordinated viarespective worm gears 305, 307, attached to a common shaft 309. Thus, inaccordance with an important feature of the invention, the rotation ofthe common shaft 309 results in the substantially identical,simultaneous movement of the support towers 215, 217. A further gearreduction is provided by a spur gear 311 attached to shaft 309 andindexed to a pinion gear (not visible in this view). One exemplarygearing arrangement will be discussed in greater detail below withrespect to FIG. 7.

[0054] The pinion gear is attached to a common shaft 315 that alsocarries a handle 313 that may be manipulated by an operator. The handlealso preferably further includes an exposed socket on a common axis withthe shaft 315, allowing the handle to be alternatively turned via anelectric screwdriver or other rotary tool. This feature may aid theoperator when there is insufficient time to turn the handle by hand therequired number of turns to provide the necessary counterbalance.

[0055] It will be appreciated that rotation of the handle 313 will causea rotation of gears 301, 303, and a subsequent coordinated raising orlowering of support towers 215, 217. In turn, the raising or lowering ofthe towers compresses the springs 205 to a greater or lesser degree,providing varying degrees of nonlinear counterbalance force to counterthe tilting of the head about tilt axis 13.

[0056] To provide a third degree of movement and adjustment, a dutchroll head may optionally be used in conjunction with the panhead. Adutch roll head rotates about a third axis, typically referred to as theroll axis. A roll axis is one that is substantially parallel with thecamera sight line axis, although the two need not be co-linear. FIG. 4illustrates a roll head assembly 401. The roll head 401 comprises a base403 fixable to the top of the panhead previously discussed by forexample a dovetail mount, and pivotally fixed to roll platform 405 atroll axis 407. Roll axis 407 preferably coincides with camera axis 409,although it is sufficient that both axes are simply substantiallyparallel.

[0057] According to an important feature of the invention, however, thecenter of gravity of the mounted camera and roll platform 405 isdisposed along the roll axis 407. In this way, the equipment balance ofthe head 1 remains unaffected by the roll of the equipment mounted onthe dutch roll head 401. In order to facilitate adjustment of the heightof platform 405, both to assure necessary clearance with the base 403and to place the center of gravity of the platform 405 and camera alongthe roll axis 407, the platform 405 is movable up and down in thedirection of axis 415. The base 403 is illustrated as being slotted topermit rod 413 to be moved vertically. However, other techniques forallowing vertical movement may also be used. For example, the platform405 may be vertically movable with respect to rod 413. In any case, themovement of the platform 405 alone or the platform 405 and rod 413 islinearly constrained, as along a dovetail mount or along a track made oftwo rods.

[0058] While alternative mechanisms may be used to allow verticalmovement of the platform 405, a rack and pinion, screw, or othersuitable mechanism is preferably employed to reduce the force needed toadjust the position of the camera and platform 405. Such mechanism maybe hand-operated, such as via a crank or other actuator. Alternatively,the mechanism may be motorized, such as thru the use of an electricmotor geared to controllably alter the vertical position of the cameraand platform 405, as will be appreciated by those of skill in the art.An exemplary geared vertical adjustment mechanism is illustrated in FIG.3 for adjusting the counterbalance force, and a similar mechanism can beused for any other vertical adjustment such as for adjustment of theroll head. Additionally, a lock 417 is provided so that the platform 405may be fixed in the desired position. The lock may employ compression ofdovetail sides, or may use any other mechanism such as a setscrew with aknob head.

[0059] A handle 411 is preferably fixed to platform 405 via shaft 413,the shaft 413 being coaxial with roll axis 407 and usable to pivot theplatform 405 about the roll axis 407. Within base 403, severalmechanisms are preferably attached to shaft 413. In particular, it maybe desirable to provide an adjustable counterbalance mechanism on shaft413 to laterally counterbalance the camera weight using the sameprinciples discussed above to provide counterbalance on the tilt axis.Such counterbalance will, however, typically not be required if thecamera center of gravity is placed as described above. Additionally, adrag mechanism is preferably indexed to shaft 413 within base 403 so asto allow for smooth camera movement about the roll axis 407. Theseelements will be discussed in greater detail hereinafter. The base 403may be fixed to the panhead using any suitable mechanism, but it ispreferable that attachment be by way of the dovetail platform to bediscussed in greater detail below.

[0060] The degree of roll attainable depends upon the dimensions of thecamera, in that interference between the camera and the base 403 willdetermine the limits of travel. Base 403 preferably exposes othercontrols usable to affect the roll behavior of the camera. Inparticular, such controls preferably include a lock 417 to prevent rollmovement of the camera about the roll axis, and a drag adjustment 419 toadjust the amount of drag about the roll axis 407. A mechanical dragindicator 421 may also be exposed on base 403, and/or an electricaloutput may supply the drag information along with counterbalanceadjustment information if counterbalance is used, and encoded rollposition information. If counterbalance is used, base 403 preferablyalso exposes a counterbalance adjustment control as discussed withrespect to the tilt axis counterbalance mechanism.

[0061] An alternative dutch roll head arrangement is shown in FIGS.4b-d. As with the previously discussed embodiment, a base 425 isprovided for attachment to a head as described herein or otherwise. Thebase comprises or is attachable to a first socket 427 for receiving ahorizontal support tube 429. A second socket 431 also receiveshorizontal support tube 429. Each of sockets 427 and 431 are fixable inrelation to horizontal support tube 429 via a clamping actionfacilitated by bolts 433 and 435 respectively, or otherwise. Secondsocket 431 has a perpendicularly oriented third socket 437 fixed theretofor receiving a perpendicularly oriented vertical support tube 439. Aclamping bolt (not shown) is usable to fix the vertical support tubewith respect to the third socket 437, in a similar fashion as bolts 431and 433.

[0062] In order to further couple a roll head support 441 to the base425, a fourth socket 443 is secured to the roll support 441 and fixedatop the vertical support tube 439 via the fourth socket 443, and via aclamping action provided by a clamping bolt 445. The roll head support441 rotatably supports an axle 447 having a roll handle 449 optionallycoupled thereto on one side. The handle 449 may be disposed in a hole inaxle 447 and fixed in place via a set screw 451, although otherattachments are envisioned. On the other side of the roll head support441, the axle 447 is attached to a roll platform 453, to which isattached, via screws or otherwise, a camera base 455. A camera 457 ismounted to the camera base 455. It will be appreciated by those of skillin the art that dutch rotation or roll of the roll platform 453, camerabase 455 and the camera 457 will occur about the axis 461 defined byaxle 447. In this embodiment, an axis 459 including the center ofgravity of the camera 457, the camera base 455 and the platform 453 isconveniently illustrated as coinciding with the sight line 459 of thecamera. Thus, those of skill in the art will appreciate that it isdesirable to align the axis 459, which includes the center of gravity,and, here, the sight line, with the dutch rotational axis 461.

[0063]FIG. 4b illustrates a possible initial mounting position of thecamera and the elements of the dutch head before adjustment of the rollaxis. FIGS. 4c-d illustrate further adjustments to better align the axisof the center of gravity 459 of the camera (about which no gravitationaltilt moment is exerted) with the roll axis 461 about which axle 447rotates. As shown in FIG. 4c, the roll platform 453 is first raisedvertically so that the central gravitational axis 459 of the camerasubstantially coincides with the roll axis 461 of the roll head 441.This adjustment may be allowed and then fixed via a set screw or othermeans, fixing the roll platform 453 in relation to the axle 447.Subsequently as shown in FIG. 4d, the camera is lowered (to attain alowest possible center of gravity for stability) while maintaining theregistration between the central axis 459 of the center of gravity andthe camera and the roll axis 461 of the roll head assembly. This is doneby loosening the clamping bolt (not shown) associated with socket 437and lowering vertical support member 439 until further substantialadjustment would cause interference between the roll platform 453 andany other member of the dutch roll head or of a pan head to which thedutch roll head may attached. After adjustment, the clamping boltassociated with socket 437 is retightened. Note that the alternativedutch roll head shown in FIGS. 4b-d preferably embodies all the sametilt locks, sensors, indicators, outputs, drag adjustment mechanisms,etc. as the head shown with reference to FIG. 4a.

[0064] Further, note that the vertical adjustment mechanisms describedwith respect to FIG. 4a may likewise be applied to the roll headarrangement shown in FIGS. 4c-d. For example, the vertical movement ofthe platform 453 and base 455, and accordingly the camera 457 may begeared due to the extreme weight of the camera 457, and such gearing maybe actuated either manually, such as via a crank, or automatically suchas via a geared electric motor. By way of further example, a gearingmechanism that can be either manually actuated, or driven by a powerscrew driver or the like may be provided. Alternately, a drive motor maybe provided. It will be appreciated that the various mounting andadjustments may also be provided in accordance with the spirit andteaching of the invention.

[0065] An alternative roll platform adjustment mechanism is shown inFIG. 4e. In particular, the roll platform 461, which is pivotable aboutthe roll axis 465 at axle 463, is vertically adjustable via a slide 467retained within a rectangular tube 469. The fit between the slide 467and the tube 469 is preferably such that the slide cannot movesubstantially in lateral dimensions, but may move vertically within thetube 469 for adjustment. Additionally, as with the other embodiments,the camera platform 471 is adjustable fore and aft, such as in adirection parallel to the roll axis 465, and is also adjustablelaterally, or side-to-side. In this manner, the center of gravity of thecamera and platform may be adjusted so that they do not exert a rollmoment or a tilt moment. Such fore and aft and lateral adjustment ispreferably, but not necessarily, effected by way of a dovetail slide andmount disposed along each direction. Once the vertical, fore and aft,and lateral positions of the camera are set, the movement of theplatform in each dimension is preferably lockable so that the balance ofthe camera package does not change during use.

[0066] Referring now to FIG. 17, an optional motor drive and actuatorfor the dutch roll head is shown schematically. In this embodiment, auser actuated actuator grip 1701 is mountable on a handle, such as a panhandle, usable to pan the camera on the pan head as described elsewhereherein. The grip 1701 may be mounted by clamps, friction fit, orotherwise. For example, the grip may have a cavity 1703 that cooperateswith the exterior of a tubular handle to secure the grip 1701 to thehandle.

[0067] The grip 1701 is electrically connected to a motor 1705. A switch1707 on the grip 1701 allows the user to actuate the motor in eitherdirection, and preferably at a rate that is proportional to the userinduced displacement of the switch 1707, such as by sliding, toggling,or rotation. The motor 1705 is geared to an axle 1711 at the roll axis,such as axle 413 of FIG. 4a, such that the actuation of the motor 1705causes the roll platform, and hence the camera package, to roll aboutthe tilt axis. The gearing of the motor to the tilt axle may be by beltdrive, chain drive, or geared drive, and preferably should use reductiongearing both to allow the motor to more easily adjust the roll, and toallow greater precision of movement. Note that the other functions ofthe roll head, such as position measurement through a rotary encoder1709, are preferably employed within this embodiment as well.

[0068] Using the actuator grip as described above, a user can pan, tilt,and roll the camera package using only one hand. This provides asmoother camera operation and eases the task of the camera operator.Additionally, the user's other hand can then be used to actuate otherdesired functions, such as drag adjustment, axis locks, and so on.

[0069] The mechanisms for adjusting the drag on each axis will now bediscussed. As mentioned previously, providing a certain amount of dragon a given axis of rotation will tend to smooth the movement about thataxis, eliminating camera overshoot and unsteadiness. Because cameras andoperators differ greatly, it is desirable to provide an adjustmentmechanism whereby the amount of drag may be preset or modified. The '568patent, already incorporated by reference in its entirety, discloses thebasic principle of viscous drag mechanisms, and the reader is referredto that patent for a full discussion of such mechanisms. The presentinvention utilizes the basic principles set forth in that patent, bututilizes an improved mechanism to actuate the drag sectors.

[0070] Referring to FIG. 6, a schematic view of an exemplary viscousdrag mechanism 601 is shown. The drag assembly 601 includes a number ofdrag sector assemblies 603 and a drag disc assembly 605. The drag sectorassemblies 603 are mounted so as to be movable linearly along a radiusof the drag disc assembly 605. The individual stacked discs 619 of thedrag disc assembly 605 are fixed to a shaft 607. In this way, when theshaft 607 rotates, the drag disc assembly 605 rotates as well.

[0071] The individual elements 619 of each of the drag sector assemblies603 are appropriately fixed relative to each element 619 in a given dragsector assembly 603 by rods and spacers 620 or other appropriatemechanism. The individual elements 619 in turn are interleavably relatedto the drag disc assembly 605. In turn, the drag sector assemblies 603are actuated in a coordinated fashion by gears 609 which are manipulatedby a user through a knob 621 or other mechanism. Thus, as the user turnsthe adjustment knob 621, the drag sector assemblies 603 becomesymmetrically more or less interleaved with the drag disc assembly 605depending upon the direction in which the knob 621 is turned. Note thatalthough a direct connection is shown between knob 621 and gear 609, anyalternative actuating arrangement may be used. For example, the knob 621may drive a worm, which drives a worm gear, which is geared to gear 609.

[0072] The spaces between stacked discs 617 of the drag disc assembly605, between the stacked individual elements 619 of the drag sectorassemblies 630, and between the stacked discs 619 and individualelements 619 are filled with a viscous fluid. A greater level ofinterleaving will create a stronger viscous drag on the drag discassembly 605 and hence on the shaft 607. Likewise, a lesser degree ofinterleaving will lessen the amount of drag associated with the rotationof shaft 607. The reader is referred to the '568 patent and U.S. Pat.No. 3,822,769 to O'Connor, hereby incorporated by reference in itsentirety for all that it teaches, for a fuller discussion of thedrag-producing interaction and environment.

[0073] The gears 609 are coordinated by interceding gears, chain andcogs, or other suitable mechanism for coordinating their movement, sothat the assemblies 603 move symmetrically with respect to disc 605.Although two drag sector assemblies 603 are shown for clarity, anynumber of such assemblies may be employed. In another embodiment, onlyone such drag sector assembly and one such disc 605 are provided foreach axis. In this presently preferred embodiment, the drag sectorassemblies 603 each comprise 23 sector pieces 619 with 22 spacerelements (see 620) located between the sector pieces 619, and each disc605 comprises 22 disc elements 617 spaced apart by 21 spacer elements(not visible) along shaft 607.

[0074] Having described the mechanical aspects of the invention indetail above, the electrical features of the panhead according to theinvention will now be discussed. In accordance with an important featureof the invention, the position of the panhead 1 with regard to thedegree which the mounted equipment is rotated about the pan axis 7,and/or tilted about the tilt axis 13, and/or the dutch head roll axis461 may be directly read by the user. In this way, a given shot may berecorded or read for later duplication, for example, or for specialeffects applied based upon a given position of the equipment. Inoverview, the electrical features provided facilitate the measurementand reporting of camera position and adjustment settings. Otherelectrical features such as backlighting for camera level indicators arealso preferably provided. In order to electronically sense the positionof the panhead 1, rotary encoders are positioned within housings 5 and11 (and dutch roll head, if utilized), as will be discussed more fullyhereinafter. The sensed positions are converted to electronic datadigitally displayable on graphical user interface panel 25 (as shown,for example, in FIG. 1). The electronic module 27 of which the graphicaluser interface 25 is a part also preferably comprises buttons andswitches usable to interact with the module to control features of thedisplay or other features such as head level backlights, as well aselectrical inputs and outputs.

[0075]FIG. 5 illustrates an exemplary graphical user interface forallowing an operator to observe measurement data and to affect theoperation of the electronic features. Note that all measurement data mayalso or alternatively be fed to the camera or image storage deviceitself, so that the camera position will be stored in direct associationwith the captured image at any point in time. Panel 501 is part ofelectronics module 503. In addition to the panel 501, the electronicsmodule 503 also exposes electrical contacts, preferably LEMO connectors,for providing and receiving electrical power and signals. Within module503 are standard electrical circuits to receive, convey, and processinformation to provide the indicated outputs and displays.

[0076] More specifically, panel 501 comprises a power button or switch505 for turning on and off the power to the electronics module 503.Another button or switch 507 is operable to turn on and off certainlights. Such lights may be, for example, back-lights, such as LEDs usedto enhance the readability of liquid bubble level devices mounted on thehead which are usable to level the camera on one or more axes.

[0077] Further, panel 501 also comprises display elements related to theposition of each axis as well as the drag setting for each axis and anycounterbalance setting for each axis. Thus, for example, row 509displays information related to the roll axis, such as head angle 511 onthe roll axis, drag setting 513 for the roll axis, and counterbalancesetting 515 for the roll axis. A reset button 517 is preferably providedfor each axis to allow the operator to set the current angle as zero, sothat subsequent angle measurements may be taken from that point. Thedisplay rows for the tilt 519 and pan 529 axes expose the same featuresand functionality, keeping in mind that a given axis may omit certainfeatures. For example, it will not be typical to provide acounterbalance or associated counterbalance adjustment reading for thepan axis, but such may be provided.

[0078] The LEMO connector ports exposed by the electronics modulepreferably include a 5 volt auxiliary power input 521, a computer output523, a remote output 525, and a roll head input 527. Although batteriestypically power the electronics module, the 5 volt auxiliary power input521 allows the operator to optionally power the electronics module viaan external 5 volt DC power source. The computer output 523 provides theinformation collected and displayed in the form of a digital data streamto be received by a separate computer through a serial port orotherwise, so that the positions and settings of the head may be trackedand stored in the computer. The remote output 525 outputs head positionand setting data in a digital or analog form usable by a remote displaymodule. This function allows the operator to attach a remote displaymodule to the remote output 525 via a cable and to place the remotedisplay module in a location where the operator may conveniently viewand/or record all or some of the data available on the panel 501. Forexample, the operator may place the remote display module adjacent tothe camera eyepiece via an adhesive or mechanical connection forconvenient and instantaneous viewing of head data.

[0079] While those of skill in the art will readily appreciate how toconfigure the circuitry of the electronics module to provide the desiredbehavior, certain features will be expressly set forth for theconvenience of the reader. The electronic components within theelectronics module may be placed on separate circuit boards, but it hasbeen found that the use of a single dual sided circuit board is morecompact and robust. Furthermore, it is desirable to backlight the panel501. It has been found that an ideal way to provide such backlight is toilluminate the ends of a plurality of fiber optical cables, andterminate the non-illuminated ends of such cables at the back of the LCDdisplay that provides the display information at panel 501. While theelectronics module may be mounted on any part of the head, it has beenfound that the most convenient location for mounting the module is onthe main body above the joint between the stationary base 3 and thehousing 5, as illustrated in FIG. 1.

[0080] In order to sense the position of the drag sector assemblies 603,a potentiometer 611 is associated with the gears 609. In one exemplaryarrangement, a gear 615 is fixed to the shaft 613 of the potentiometer611. This gear 615 mates with one of the gears 609 so that rotation ofgears 609 causes a rotation of the shaft 613 of the potentiometer 611.In this way, the resistance exhibited by the potentiometer 611 gives anindication of the current position of the drag sector assemblies 603,and hence of the level of drag currently experienced by shaft 607. Inanother embodiment, the shaft 613 of the potentiometer is directlyattached to the shaft of a gear 609, providing a corresponding ratherthan simply proportional reading. The electrical outputs of thepotentiometer 611 are supplied to the electronic module 503, for use inderiving a digital representation of the current drag.

[0081] The electronic module 503 also comprises two potentiometeradjustments for each drag assembly in order to adjust the indication ofdrag given so that it travels from at or near 0% for the minimum amountof drag applied, to at or near 100% for the maximum amount of dragapplied. In particular, as those skilled in the art of electronics willappreciate, one factory settable potentiometer is provided to adjust thepercentage indicated when the drag sector assemblies 603 are minimallyinterleaved, while a second factory settable potentiometer is providedto adjust the slope of the percentage indicated as a function of theamount of interleaving. In this way, the percentage of drag indicated onpanel 501 can be adjusted so that minimal interleaving yields a readingat or near 0% while maximum interleaving yields a reading at or near100%.

[0082] A drag mechanism such as that described above is placed on eachaxis, so that the shaft 607 is rotated coincident with rotation on therelevant axis. Likewise, the drag adjustment setting on each axis isrelayed to the electronic module 503 and is displayed in the appropriatelocation on the panel 501.

[0083] The remaining mechanisms usable to collect data for display onpanel 501 will now be discussed in greater detail. Turning first toFIGS. 3 and 7, gears 301, 303 are driven via respective worm gears 305,307, attached to a common shaft 309, and a further gear reduction isprovided by a spur gear 311 attached to shaft 309 and indexed to apinion gear. Referring to FIG. 7, a portion of the above gearingarrangement is shown in greater detail. Like numerals indicate likecomponents, i.e., elements 709, 711, 713, and 715 of FIG. 7 correspondto elements 309, 311, 313, and 315 of FIG. 3.

[0084] The gearing arrangement of FIG. 7 provides for an electronicreading of the counterbalance position in the following manner. Whenknob 713 is rotated, in turn rotating pinion 717 and consequently spur711, the counterbalance support towers 215, 217 are raised or loweredaccordingly, adjusting the degree of counterbalance applied. At the sametime, worm gear 719 fixed to common shaft 715 is rotated. This causesmating gear 725, fixed to the shaft 723 of potentiometer 721, to rotateas well, changing the resistance of the potentiometer 721. The leads ofthe potentiometer 721 are supplied to the electronic module 503 in orderto give an indication of counterbalance applied on the relevant axis.Each axis that is counterbalanced has an associated potentiometer formeasuring the counterbalance position as, for example, described above,and a corresponding display is provided at panel 501. As described abovewith respect to the calibration of drag position indication, eachposition measuring potentiometer is associated with two calibrationpotentiometers in the electronic module 503, usable to calibrate theindication of counterbalance displayed on panel 501.

[0085] Within an embodiment of the invention, the position of the headitself is measured and displayed to the user via panel 501. In thiscase, it is desirable to use precision rotary encoders rather thansimple resistance measurements because greater accuracy may thus beobtained. Exemplary rotary encoders are commercially available. Forexample, the High-Sensing Accuracy Optical Photo Interpreter, partnumber GP1A35RV, sold by SHARP ELECTRONICS may be used to encode themovement of an appropriately slotted disc. FIG. 8 schematicallyillustrates the basic configuration of a rotary encoder in use. Anencoder disc 801 is attached to a shaft or other rotation center ofinterest so that the disc rotates when the rotation center rotates.Typically, the rotation center and the disc 801 are arranged to remainin a fixed angular relation to one another, although the disc may alsobe geared up or down to the rotation center of interest. The disc isperforated with slots 803 that are typically approximately severalthousandths of an inch wide and deep. For example, the slots 803provided with the GP1A35RV are 2 thousandths of an inch wide and 2thousandths deep, corresponding to the axial thickness of the disc atthe location of a slot.

[0086] A pick-up 805 having a slot 807 is situated such that the sides809, 811 of the slot are in a straddling relationship with the disc 801.One or more light sources such as LEDs or laser diodes reside within oneof the sides 809, while one or more light detection devices such asphotodiodes or other devices reside in the other side 811. The lightsource and light detection devices are situated so that light from alight source in side 809 passing through a slot 803 is detected by alight detection device in the other side 811. In this manner, the motionof the disc is detected electronically and an indication of the motionis transmitted on leads 813. It is preferable that the disc 801 andpick-up 805 combination selected also detect the direction of movementof the disc 801. In addition, although the preferred encoding mechanismoperates via light transmission, other systems, such as those thatoperate using reflectance rather than transmission may also be used.Also, the described encoders are absolute encoders as are preferable forbest accuracy. However, other types of encoders such as relativeencoders may also be used alternatively.

[0087] An encoder disc/pick-up combination such as that described aboveis preferably placed on each axis of movement for which it is desired todisplay position information. Preferably, position information isdisplayed for each axis, i.e. the roll, tilt, and pan axes. FIG. 9 showsa schematic cross section of a panhead according to an embodiment of theinvention in the plane defined by axes 7 and 13 of FIG. 1, at the levelof axis 13. Housing 901 and shaft 903 define a first annular cavity 907centered about shaft 903, while housing 901, endplate 905, and shaft 903define a second annular cavity 909 centered about shaft 903.

[0088] The first annular cavity 907 contains an adjustable dragmechanism as discussed with respect to FIG. 6. In particular, an annulardrag disc assembly 915 is fixed to shaft 903 so as to rotate therewith,while one or more drag sector assemblies 917 are fixed with respect tothe housing 901 except that they may be adjusted along a radius of axis13. Adjustment of these drag sector assemblies 917 affects the dragassociated with the rotation of shaft 903 in the manner described withrespect to FIG. 6.

[0089] A slotted encoding disc 911 such as the disc 801 of FIG. 8resides within cavity 909, being fixed upon and co-axial with shaft 903.A pick-up 919 such as pick-up 805 of FIG. 8 is situated within cavity909 as well, being fixed to housing 901 so as to straddle encoding disc911 as the disc rotates. Shaft 903 is also fixed to the tiltingcomponents of the panhead and defines the axis of tilting.

[0090] Accordingly, as the camera is tilted, in turn tilting the tiltingcomponents of the head, shaft 903 rotates in registration with thecamera, causing disc 911 to rotate as well. As disc 911 rotates, theslots of the disc alternatingly pass and block light within the pick-up909, creating an electrical signal indicative of the motion of thecamera about the tilt axis 13. As discussed above, this signal isconveyed via electrical leads to the electronics module 913,corresponding to module 503 of FIG. 5, which then interprets anddisplays the information as a percentage of the range of available tiltmotion. Note that the user may use the reset button for a given axissuch as element 517 in FIG. 5, to set the current camera position as thezero position with respect to which future positions may be measured.

[0091] Note that the various cavities defined within the head and rollhead may be changed, so that for example, more of the cavity is definedby one piece than by another, and so on. The only matter of consequenceis that such a cavity somehow be defined. Also, note that the relationbetween the cavities 907, 909 need not be as shown. For example, thecavities, and associated elements, may be disposed on opposite sides ofthe head, rather than on the same side, such that one end of the axle903 is associated with the drag mechanism, while the other end of theaxle 903 is associated with the rotary measurement mechanism. Similarly,a tilt brake and tilt lock if used may be disposed at whichever end ofthe shaft 903 is convenient, and need not be on the same side as eachother.

[0092] In a similar fashion, the position information for the other axesis measured and conveyed to the electronics module 913 for display. FIG.10 is a cross sectional view of the panhead taken in a plane defined byaxes 7 and 13, viewed at the level of line 29. FIG. 10 schematicallyillustrates an exemplary position sensing mechanism for measuring theposition of the camera about the pan axis 7. In particular, the base1001 is fixed relative to a tripod or other support, while the upperhousing 1011 which supports the remainder of the panhead is rotatablydisposed upon the base 1001 and coupled thereto via a large bolt 1019and washer assembly received in a channel in the upper housing 1011.

[0093] A plurality of bearings1013, 1015, 1017 are preferably employedto minimize the friction of rotation and to bear the considerable weightof the camera and the upper portion of the head, all of which can rotateabout axis 7. The bearings 1013 may be any suitable type, such asTimpkin tapered bearings, adapted to support both axial and radialloads. Bearings 1015 are preferably disposed to bear axial loadassociated with the central axle attachment between the upper housing1011 and the base 1001. Suitable bearings for this purpose include anybearing capable of bearing the magnitude and direction of stressapplied, such as Torrington thrust bearings. Bearings 1017 are situatedso as to bear radial loads between base 1001 and the lower part of upperhousing 1011. Note that the bearings 1015 and 1017 provide a balancingload for the preloaded the tapered bearings 1013 in the illustratedarrangement. As will appreciated by those of skill in the art, any othersuitable number, type and arrangement of bearings may be used instead ofthe illustrated configuration.

[0094] The base defines two annular cavities 1021 and 1023. The firstannular cavity 1021 contains an adjustable drag assembly 1003 similar instructure and operation to that described above with respect to the tiltaxis, the adjustment position of which is measured and displayed asdescribed above. Thus, the cavity 1021 additionally contains a suitableviscous fluid, such as one of the many silicon-based fluids familiar tothose of skill in the art. The second annular cavity 1023 contains anencoder disc 1025 and pick-up 1009, operating in substantially the samemanner as described above with respect to the tilt axis, to measure andrelay the pan axis rotation position for display to the user. Note thatin the illustrated embodiment, the pick-up 1009 rotates with the upperhousing 1011, while the encoder disc 1025 remains fixed relative to thebase 1001. However, those of skill in the art will appreciate thatappropriate relative motion may also be achieved by fixing the pick-up1009 relative to the base and allowing the disc 1025 to rotate with theupper housing 1011.

[0095] Note that a pan axis lock may also be employed to lock therotation of the upper housing 1011 relative to the base 1001. Thisgenerally requires a moving locking piece fixed to the housing 1011 anda stationary locking piece fixed to the base 1001. Locking of the panaxis is effected by locking the moving and stationary locking piecestogether. Typically, one locking piece will be a disc and the other adisc clamp or other locking mechanism.

[0096]FIG. 11 is a cross sectional view of the roll head attachmenttaken in a plane defined by axis 407 and vertical axis 421 in FIG. 4a.Note that although not shown in detail in this figure, the camera ispreferably adjustable both fore and aft and side to side, so that thecenter of gravity of the camera exerts neither a roll moment nor a tiltmoment. The adjustments may be made by way of sliding dovetails anddovetail mounts or otherwise, as will appreciated by those of skill inthe art. The housing 1101, corresponding to housing 403, preferablycontains a damping mechanism and a position encoding mechanism, and mayalso contain a counterbalance mechanism. In particular, a first annularcavity 1103 contains an adjustable drag assembly 1105 similar instructure and operation to that described above with respect to the tiltaxis, the adjustment position of which is measured and displayed asdescribed above. A second annular cavity 1107 contains an encoder disc1109 and pick-up 1111, operating in substantially the same manner asdescribed above with respect to the tilt axis, to measure and relay theroll axis rotation position for display to the user.

[0097] The housing 1101 optionally defines a third annular cavity 1113,containing an adjustable counterbalance mechanism, preferably of thedesign described above or alternatively as described in the '568 patent.If a counterbalance mechanism is employed to counterbalance the cameraabout the roll axis, its setting is preferably detected, relayed andindicated to the user as described above with respect to the tilt axis.Note that since the roll head attachment is optional, the electricalsignals relating to the damping, counterbalance, and position of theroll head are carried by a separate cable having a male LEMO connectorto be plugged into port 527 of the electronics module 503. Note that theaforementioned features of the dutch roll head are preferably alsoincluded in an embodiment as illustrated in FIGS. 4b-d.

[0098] As discussed above, the electronic features of the panheadtypically receive electrical power from a portable battery pack that isaffixed to the head or to the tripod or other support. An exemplaryconstruction for the battery pack is illustrated in cross sectional viewin FIGS. 12a and 12 b. FIG. 12a shows the battery pack completelyassembled while FIG. 12b shows the battery pack completely disassembled.The battery pack is constructed of three mating pieces, a battery holder1201, a first top 1203 and a second top 1205. The battery holder 1201and the first top 1203 are made primarily of electrically nonconductivematerial such as plastic, while the second top 1205 is made primarily ofelectrically conductive material such as aluminum. The battery holder1201 contains a bottom contact 1207 for contacting a bottom battery 1209shown in outline in FIG. 12a. The bottom contact 1207 is electricallyisolated from the battery holder 1201, but is in electrical contact withpin 1211 via a wire, not visible in these illustrations, when thebattery pack is assembled as in FIG. 12a.

[0099] The pin 1211 in the first top 1203 serves to provide electricalcontact between the bottom contact 1207 and the body of second top 1205.A central contact 1213 in first top 1203 makes electrical contact withthe positive end of the series of batteries within holder 1201 when thepack is assembled as in FIG. 12a. In turn a central contact 1215 insecond top 1205 makes electrical contact with the central contact 1213when the pack is assembled as in FIG. 12a. A spring 1217 allows forvarying tolerance of the placement of the second top 1205 with respectto the first top 1203. In this manner, the negative or ground voltage ofthe batteries in the pack is exposed to the panhead via top 1205, whilethe positive voltage is exposed via contact 1215. Note that contact 1215is electrically isolated from top 1205.

[0100] The fit and function of the battery pack are illustrated inperspective view in FIG. 13 for the convenience of the reader. Elements1301, 1303, 1305, 1311, 1313, and 1315 correspond to elements 1201,1203, 1205, 1211, 1213, and 1215 respectively of FIGS. 12a and 12 b. Itcan be seen that the battery pack described herein allows a user toquickly change batteries in two different ways. In particular, the usermay rotate and pull the holder 1301 to detach it from the first andsecond tops 1303, 1305. Once the batteries in the holder are exchangedfor fresh batteries, the user may push and rotate holder 1301 toreassemble the battery pack. Alternatively, the user may push and rotateboth the holder 1301 and first top 1303, disengaging them as a unit fromsecond top 1305. In this manner, another assembled holder and first topmay replace the removed unit to provide fresh electrical power.Preferably, the battery pack is assembled to a panhead using the samesteps of linearly advancing the battery pack toward the panhead, andaxially rotating the battery pack to make the electrical connections.While the holder 1301 and first and second tops 1303, 1305 areillustrated as cylindrical in shape, it will be appreciated thatalternate shapes may be provided.

[0101] Note that in either manner of changing out the battery pack fromthe panhead, power to the electronics module will be interruptedmomentarily. For this reason, it is desirable that the electronicsmodule incorporates a capacitor or other electrical energy storagedevice to provide a short period, such as thirty seconds, of reservepower during battery change. While the battery pack is preferablyadapted to accommodate 2 “C” size cells, any other number and size ofcells may equivalently be used.

[0102] Because the panhead and related components as described hereinare generally intended for use with heavy cameras or other equipment,according to another feature of the invention, an improved mechanism formounting the camera to the panhead is provided. In particular, it isdifficult and inconvenient to be forced to slide a heavy camera or rollhead mounted on a dovetail platform completely out of a dovetail basebefore being able to remove it. Even with dovetail bases that wouldallow a dovetail side to be forced down to permit camera removal, theoperator is required to manually force the side down. Unfortunately,clearances are generally such that this is often difficult orimpossible.

[0103] In an embodiment of the invention, a novel dovetail base isprovided that allows an operator to automatically lower one dovetailside by simply moving a lever. FIG. 14 shows a perspective view of thenovel base 1401, with a dovetail platform 1403 mounted. In operation,the dovetail rail assembly or platform 1403 is mounted to the bottom ofthe camera or roll head via screw holes 1405, and is then mounted on thedovetail base 1401 by being compressed between dovetail sides 1407shaped to mate with the platform 1403. A lever 1409 is provided and isadapted to compress the dovetail sides 1407 when pushed in one directionB, and to uncompress the dovetail sides 1407 and then drop one of sides1407 when pushed in the other direction A. The platform 1403 is indexedto the base 1401 via a rack and pinion mechanism to be more fullydescribed below. Note that screw holes 1411 are used to attach the rackto the underside of the platform 1403.

[0104]FIG. 15 shows a schematic bottom view of the platform 1401,including one dovetail side 1501 (see also 1407 in FIG. 14). This viewis provided so that user may understand the mechanism by which thedovetail sides are pressed together. Manipulation of lever 1509 can beused to either cause dovetail side 1501 to move toward and mate withdovetail platform 1503, or to cause dovetail side 1501 to move away anddownward from dovetail platform 1503. According to the presentlypreferred embodiment, one dovetail 1501 of the platform moves to allowplacement of the dovetail platform 1403, as explained herein, while thedovetail 1407 along the opposite side of the platform 1403 remainsstationary. In this way, the user simply places one edge of the dovetailplatform 1403 underneath the stationary dovetail 1407, and thenactivates the opposite dovetail 1501 to clamp the platform 1403 inposition.

[0105] In particular, as lever 1509 is pushed in a clockwise direction,it exerts a pull force on first link 1521, pivoting lever 1523, to whichit is hinged, about pivot 1525, thus exerting a leveraged pull forcealong dogbone 1527, which is hinged to lever 1525. Dogbone 1527 in turnpulls on and rotates link 1529 clockwise about pivot 1531. This motioncauses symmetrical pulling motions by side pieces 1535 and 1533. Withthe left portion of the assembly as illustrated, the movement of dogbone1527 causes link 1529 to pivot about pivot point 1531, causing aclamping or downward motion as viewed on side piece 1535 via short link1537. This clamping motion is transmitted to the opposite side piece1533 of the dovetail side 1501 by link 1545, which causes link 1563 torotate about pivot 1543 and place a downward clamping force on sidepiece 1533 via short link 1539. In this way, the rotation of the lever1509 clockwise will compress as dovetail side 1501 exerts a forceagainst dovetail platform 1503, locking the camera in position withrespect to the dovetail base 1561.

[0106] Conversely, moving the lever 1509 in a counterclockwise directionserves to move dovetail side 1501 away and downward from dovetailplatform 1503, effectively allowing the camera and platform 1503 to besimply lifted off the base 1561. The mechanism by which this occurs isillustrated in greater detail in FIG. 16. FIG. 16 shows a schematicpartial cross sectional view of a plane defined by axes 7 and 13 ofFIG. 1. FIG. 16a shows the mechanism in a compressed position, i.e.,clamped with dovetail side 1601 pressed against a mating surface ofdovetail platform 1603. In this view, it can be seen that dovetail side1601 is pivotally linked to side piece 1635 corresponding to side piece1535 at pivot 1619. Corresponding side piece 1633 is hidden from viewbehind side piece 1635, but acts identically to side piece 1635.

[0107] According to one feature of the invention, the dovetail side 1601physically moves outward and downward to allow the dovetail platform1603 to be easily placed and located beneath the stationary dovetailside along the opposite edge of the dovetail platform 1603. In this way,as lever 1509 of FIG. 15 is moved from its compressed position in acounterclockwise direction, the reverse process to that described aboveoccurs; that is, side piece 1635 pushes dovetail side 1601 away fromplatform 1603. The dovetail side 1601 is then physically moved downward,through the horizontal plane by a camming arrangement. In the presentlypreferred camming arrangement, this movement is the result of theengagement of a trip lever 1611 and a trip catch 1613, although othercamming arrangements are likewise within the spirit and scope of theinvention.

[0108] As can be seen in FIG. 16b, as dovetail side 1601 moves away,trip lever 1611, which is pivotally mounted to dovetail side 1601 at1617, slides to engagement with the downward projection of trip catch1613. Both the trip lever 1611 and the dovetail 1601 are biased upward.Trip catch 1613 is fixed to base 1561 as shown and does not move withdovetail side 1601. Consequently, as side piece 1635 continues to pushdovetail side 1601 away from platform 1603, trip lever 1611, which canno longer move linearly because it abuts catch 1613, rotatescounterclockwise, exerting a clockwise rotational force on dovetail side1601, forcing it downward, as seen in FIG. 16c.

[0109] The clockwise rotational force depends upon the pivot point 1617of the trip lever 1611 being lower than the pivot point 1619 betweenside piece 1635 and dovetail side 1601. Theoretically, the force exertedalong link lever 1611 can be resolved into two perpendicular components.One component 1621 is directed along the line between pivot points 1619and 1617, and this component has no effect and produces no movement. Theother component 1623 is perpendicular to the line between pivot points1619 and 1617, and it is this component that produces the clockwiserotation that moves the side piece 1601 downward from platform 1603.

[0110] While the trip lever 1611 has been shown pivotably coupled to theside piece 1601 and the trip catch 1613 fixed to the base 1561, it willbe appreciated by those of skill in the art that the trip lever couldalternately be pivotably coupled to the base and the trip catch fixed tothe side piece. Under such an arrangement, the trip lever could slidealong the upper surface of the side piece until it engages the tripcatch at which time continued force exertion would cause the side pieceto pivot the dovetail side down and through the horizontal plane. Insuch an arrangement, the pivot axis of the trip lever would be disposedabove, rather than below, the pivot axis of the side piece. These arebut two examples of how such a camming arrangement may be incorporatedto provide the lowering movement of the dovetail side. It is furtherwithin the invention, as will be appreciated by those of skill in theart, to actuate the dovetail side 1601 such that substantial lateralmovement is not required before downward movement of the side 1601commences.

[0111] Returning to FIG. 15, once the dovetail platform 1503 is placedon the base, but before it is locked into position by the force ofdovetail side 1501, it is desirable to adjust the position of the camerafore and aft to properly place the camera center of gravity. In theplatform according to an embodiment of the invention, a pinion gear 1547is used to move rack 1549 thus moving the dovetail platform 1503 andattached camera. This movement may be provided by way of a rotatableknob 1559, which is coupled to the pinion gear 1547. More specifically,pinion 1547 is secured to shaft 1551. A helical gear 1553 is alsoattached to the shaft 1551 and is also mated to a helical gear 1555. Inturn, the helical gear 1555 is attached to a shaft 1557 that the usermay turn by turning attached knob 1559. In this manner, the user mayconveniently use knob 1559 to move the dovetail platform 1503 fore andaft to properly place the camera center of gravity once the platform1503 is resting on but not locked to the base.

[0112] It will be appreciated that a new and novel camera panhead,rollhead, mounting system, and power system have been described herein.In view of the many possible embodiments to which the principles of thisinvention may be applied, it should be recognized that the embodimentsdescribed herein with respect to the drawing figures are meant to beillustrative only and should not be taken as limiting the scope ofinvention. For example, those of skill in the art will recognize thatthe illustrated embodiments can be modified in arrangement and detailwithout departing from the spirit of the invention. Therefore, theinvention as described herein contemplates all such embodiments as maycome within the scope of the claims and equivalents thereof.

I claim:
 1. A panhead for supporting equipment and providing movementfrom a vertical position to a tilt position, said panhead comprising, incombination, a tilt housing, a tilt drum defining a tilt axis, said tiltdrum being mounted within said housing for rotation about said tiltaxis, at least four springs, said springs forming at least two separatepairs of springs, mounted in substantially perpendicular planes to saidtilt axis, a common axis disposed substantially parallel to the tiltaxis, at least one mount for mounting one end of each of said springspivotally along a common horizontal axis, said common axis lying belowsaid tilt axis in a vertical plane containing said tilt axis, wherebythe end of one spring in each pair of springs coupled to the common axisis mounted between the ends of the other pair of springs coupled to thecommon axis, the spring pair mountings to the common axis beingstaggered, and a plurality of mounts for coupling the opposite ends ofeach pair of said springs to the tilt drum for rotation therewith, saidpairs of springs being mounted at an angle to a substantially verticalplane containing the tilt axis when said panhead is in said verticalposition, whereby said springs exert a restoring torque when the tiltdrum is tilted from said vertical position to said tilt position.
 2. Thepanhead according to claim 1 further comprising an adjustment gearingfor controllably positioning the common axis relative to the tilt axis.3. The panhead according to claim 2 further comprising a common axleoriented substantially along the common axis, the one end of saidsprings being coupled to said common axle, the adjustment gearingfurther comprising at least two rotatably mounted vertical threadedshafts, each threaded shaft having an axis of rotation, the axes of thethreaded shafts being substantially fixed relative to the tilt axis, thethreaded shafts being threadably coupled to said common axle wherebyrotation of the threaded shafts moves the common axle to vary thedistance between the common axis and the tilt axis.
 4. The panheadaccording to claim 3 wherein the adjustment gearing further comprises asynchronizer for rotationally indexing each screw to the other.
 5. Thepanhead according to claim 1 further comprising a tilt drag assembly forexerting a drag force against rotation of the tilt drum.
 6. The panheadaccording to claim 1 further comprising a vertical pan shaft defining avertical pan axis, and a base housing for mounting said tilt housing onsaid vertical pan shaft for rotation about said vertical pan axis. 7.The panhead according to claim 6 further comprising a pan drag assemblyfor exerting a drag force against rotation of the housing on saidvertical pan shaft about said vertical pan axis.
 8. The panheadaccording to claim 6 further comprising a first integral rotary sensordisposed within the tilt housing and adapted to sense rotation of thetilt drum about the tilt axis and output a first signal indicative ofthe rotation of the tilt drum about the tilt axis.
 9. The panheadaccording to claim 8 further comprising a second integral rotary sensordisposed within the base housing and adapted to sense rotation of thetilt housing about the pan axis and output a second signal indicative ofthe rotation of the tilt housing about the pan axis.
 10. The panheadaccording to claim 9 further comprising a display unit for displaying afirst display related to the rotation of the tilt drum about the tiltaxis and a second display related to the rotation of the tilt housingabout the pan axis, wherein the first and second displays are derivedfrom the first and second signals respectively.
 11. The panheadaccording to claim 10 further comprising a roll head mounted to thepanhead for rotation of the supported equipment for rotation of thesupported equipment about a roll axis, the display unit furthercomprising an input for receiving a third signal indicative of an amountof roll about the roll axis experienced by the roll head mounted to thepanhead, and a third display related to the amount of roll about theroll axis experienced by the roll head, wherein the third display isderived from the third signal.
 12. The panhead according to claim 10wherein the display unit further comprises a plurality of furtherdisplays for displaying at least an indication related to the restoringtorque exerted about the tilt axis when the tilt drum is tilted from anequilibrium position.
 13. The panhead according to claim 7 furthercomprising a tilt drag assembly for exerting a drag force againstrotation of the tilt drum, and a display unit for displaying anindication related to an amount of drag force exerted against rotationof the tilt drum about the tilt axis or the tilt housing about the panaxis.
 14. The panhead according to claim 13 further comprising a rollhead mounted to the panhead for rotation of the supported equipmentabout a roll axis, the display unit further comprising a roll displayfor displaying an indication related to an amount of drag force exertedagainst rotation of the roll head about the roll axis.
 15. Acounterbalance for use in exerting a counterbalancing force when movedfrom a vertical position to a tilt position about a tilt axis, thecounterbalance comprising: a drum that is rotatable about the tilt axis;a common axle that is not rotatable about the tilt axis, said commonaxle having a common axis which is parallel to the tilt axis; at leasttwo common axle supports supporting the common axle; first and secondlateral axes disposed along either side of a vertical plane containingsaid tilt axis, each said lateral axis being disposed parallel to butnot collinear with the tilt axis, said first and second axes beingdisposed for rotation with said drum about the tilt axis; a first pairof compressive spring assemblies coupled both to the common axle througha first pair of couplings and at said first lateral axis; a second pairof compressive spring assemblies coupled both to the common axle througha second pair of couplings and at said second lateral axis, whereby oneof the first set of couplings lies between the second pair of couplingsalong the common axle, the spring pair mountings to the common axis thusbeing staggered; and a first rotary sensor for sensing the rotation ofthe drum about the tilt axis, and for producing an electrical tiltoutput indicative of the amount and direction of rotation of the drumabout the tilt axis.
 16. The counterbalance according to claim 15wherein the first lateral axis is disposed a first distance from thecommon axis, and the second lateral axis is disposed a second distancefrom the common axis, said the first and second distances beingsubstantially equal in the vertical position, rotation of the drum fromthe vertical position to the tilt position lengthening one said distanceand shortening the other said distance such that the compressive springassemblies produce said counterbalancing force about the tilt axis, saidcounterbalance further comprising a counterbalance adjustment mechanismincluding an adjustment that moves the common axle towards or away fromthe tilt axis, adjusting the first and second distances to adjust thecounterbalancing force exerted by the compressive spring assemblies. 17.The counterbalance according to claim 15 further comprising a tilthousing external to and enclosing the drum, the common axle, the firstand second pairs of compressive spring assemblies, and said first rotarysensor.
 18. The counterbalance according to claim 17 further comprisinga base housing, and a pan axle on a pan axis about which the tilthousing may rotate, said base housing housing the pan axle.
 19. Thecounterbalance according to claim 18, further comprising within the basehousing a second rotary sensor for sensing the rotation of the tilthousing about the pan axis and for producing an electrical tilt outputindicative of the amount of rotation of the tilt housing about the panaxis.
 20. A dovetail mount for retaining a removable dovetail rail, thedovetail mount being adapted to secure the removal dovetail rail to apanhead of an equipment supporting device, the dovetail mountcomprising: a pair of opposed dovetail sides forming a dovetail track,at least one of said dovetail sides being movable; a movable lockinglever; and an actuable coupling mechanism extending between the movabledovetail side and the lever; said locking lever being movable in a firstdirection for pressing the movable dovetail side toward the opposeddovetail side, thereby retaining the removable dovetail rail, saidlocking lever being movable in a second direction to move the movabledovetail side away from the opposed dovetail side in a horizontal plane,movement of the locking lever past a threshold point in the seconddirection further acting to lower the movable dovetail side through thehorizontal plane, allowing the removable dovetail rail to be disengagedfrom the dovetail track.
 21. The dovetail mount according to claim 20wherein the actuable coupling mechanism comprises a camming arrangementto lower the movable dovetail side through the horizontal plane.
 22. Thedovetail mount according to claim 20 wherein the actuable couplingmechanism comprises at least one movable arm pivotably coupling thelocking lever to the movable dovetail side at a first pivot axis, andthe camming arrangement comprises a catch and at least one trip leverpivotably coupled at a second pivot axis, said trip lever being disposedto engage said catch as said locking lever is moved past said thresholdpoint in the second direction, said trip lever rotating about saidsecond pivot axis to exert a force on said movable dovetail side torotate the movable dovetail side about said first pivot axis to lowerthe movable dovetail side through the horizontal plane.
 23. The dovetailmount according to claim 22 wherein the trip lever is pivotably coupledto the movable dovetail side.
 24. The dovetail mount according to claim22 wherein the catch is secured to the movable dovetail side.
 25. Thedovetail mount according to claim 20, further comprising at least onepair of mating rack and pinion gears secured to the removable dovetailrail and the dovetail track, whereby the position of the removabledovetail rail within the dovetail track can be adjusted by rotating thepinion before fixing the removable dovetail rail to the dovetail track.26. A quickly detachable battery power source including at least onebattery having two terminals for powering electric functions of apanhead, the battery power source comprising; first and second leadsadapted to be electrically coupled to the battery terminals; a housingfor holding at least one said battery, said housing having a first endand a second closed end; and a closure for placement at the first end ofthe housing after insertion of the at least one battery, such that priorto fixed placement of the cylindrical closure at the first end of thehousing, a voltage difference is not measurable across the first andsecond leads, and a voltage difference is measurable across the firstand second leads after fixed placement of the closure at the opening ofthe housing.
 27. The battery power source according to claim 26 whereinfixed placement of the closure at the first end of the housing requiresapplication of first force along an axis of the housing, followed byapplication of a second force along an angular direction relative to theaxis of the housing, whereby the closure resists removal forces appliedalong the axis of the housing.
 28. An electronic panhead display packagefor displaying a readout corresponding to at least one angulardisplacement associated with a panhead, comprising the battery powersource according to claim 27, and further comprising a processing unitand a backup power source, so that if the cylindrical closure is removedfrom the cylindrical housing, the backup power source will supplyelectrical power temporarily to the processing unit.
 29. A method forcoupling a battery power source to a panhead to power electricalfunctions of the panhead, the method comprising the steps of providing abattery power source having a housing and having a first lead disposedat an end face the housing and a second lead extending from a sidesurface of the housing, linearly advancing the end face into engagementwith the panhead, and rotating the battery housing to engage the leadswith electrical connections of the panhead.
 30. A panhead for supportingequipment, said panhead including: a stationary base, a platform forsupporting said equipment, said platform being moveable relative to saidstationary base, at least one of a mechanism for tilting said platformrelative to said base or a mechanism for rotatably panning said platformrelative to said base, at least one integral sensor adapted to sensetilting of said platform relative to said base or adapted to senserotational panning of said platform relative to said base, said integralsensor producing a signal, and at least one display for displaying saidsignal.
 31. The panhead of claim 30 comprising both a mechanism fortilting said platform relative to said base and a mechanism forrotatably panning said platform relative to said base, both an integralsensor adapted to sense tilting of said platform relative to said base,and an integral sensor adapted to sense rotational panning of saidplatform relative to said base, said integral sensors producingrespective signals reflective of tilting motion and reflective ofrotational panning motion, and at least one display for displaying bothsaid signals.
 32. The panhead of claim 30 comprising at least oneintegral rotary sensor.
 33. A counterbalance for use in exerting acounterbalancing force when moved from a vertical position to a tiltposition about a tilt axis, the counterbalance comprising: a drum; atilt axis within said drum; a common axle within said drum, said commonaxle having a common axis that is parallel to the tilt axis; first andsecond lateral axes disposed along either side of a vertical planecontaining said tilt axis, each said lateral axis being disposedparallel to but not collinear with the tilt axis; a first pair of springassemblies coupled both to the common axle through a first pair ofcouplings and at said first lateral axis; and a second pair of springassemblies coupled both to the common axle through a second pair ofcouplings and at said second lateral axis, whereby one of the first setof couplings lies between the second pair of couplings along the commonaxle, the spring pair mountings to the common axis thus being staggeredone of either the common axle or the first and second lateral axes beingrotatable about the tilt axis, the other being rotatably fixed relativeto the tilt axis whereby said spring assemblies exert saidcounterbalancing force during such rotation.
 34. The counterbalance ofclaim 33 wherein said common axle is rotatable about the tilt axis, andsaid first and second lateral axes are rotationally fixed relative tothe tilt axis.
 35. The counterbalance of claim 33 wherein said commonaxle is not rotatable about the tilt axis, and said first and secondlateral axes are rotatable about the tilt axis.
 36. A dutch roll headfor providing a roll function to a camera, the dutch roll head beingremotely actuable by a user, comprising: a roll axle disposed along aroll axis; a motor connected to the roll axle for causing rotationthereof about the roll axis; and a user grip adapted for mounting on ahandle, whereby the grip may be used to move the handle; and anelectronic interface element mounted on the user grip linked to themotor via an electronic link and adapted to be actuated by said user,whereby when said user actuates the interface element by a given amount,a signal is transmitted via the electronic link to the motor causing themotor to effect a rotation of the roll axle in an amount proportional tothe given amount by which the user actuates the interface element. 37.The dutch roll head according to claim 36, wherein the interface elementis selected from the group consisting of a sliding switch, a rotaryswitch, and a toggle switch.